client: add support for 'in' operator
client: add support for 'in' operator

The 'in' operator has been renamed _in to avoid conflict with Python 'in'
operator.
The 'in' operator can be used to get a limited set of items.

Change-Id: If3b0a670b5f2315fc2acc15752e3dac2bfbb4d9c

goneri/dci-control-server,redhat-cip/dci-control-server,goneri/dci-control-server,goneri/dci-control-server,enovance/dci-control-server,goneri/dci-control-server,enovance/dci-control-server,redhat-cip/dci-control-server